A USB device comprises a USB connector 1 for connecting it to a USB or HUB of a host and a serial interface engine (SIE) 2 serving as an interface. The USB connector 1 and the SIE 2 are interconnected by four signal lines defined in a USB. Of these signal lines, a 5-V power supply line for supplying 5-V power to the SIE 2 is provided with a switch 3 for electrically on-off switching it. The user can readily control the power supply from the host to the USB switch by operating the switch. Thus, when the USB device is not used, the power supply from the host can be stopped to reduce power consumption of the host.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A USB connecting system in which a USB device is connected by a USB interface to an upper rank unit either directly or via an HUB, wherein: the upper rank unit includes a driver for sending out a control signal for turning off the power supply to the USB device; the USB device includes: power supply control means for on-off switching a 5-V power supply line for transmitting 5-V power supplied from the upper rank unit to the USB device and data lines for supplying data from the upper rank unit to the USB device side and transmitting data from the USB device side to the upper rank unit; and USB control means for transmitting a setting signal for disconnecting the 5-V power supply line and the data lines to the power supply control means when recognizing the control signal for turning off the power supply from the driver to the USB device; and power supply control means disconnects the data lines and then disconnects the 5-V power supply line in response to the setting signal from the USB control means for disconnecting the 5-V power supply line and the data lines.
2. The USB connecting system according to claim 1 , wherein: the USB device includes input means for inputting settings from an operator; and power supply control means connects the 5-V power supply line and then connects the data lines when a setting for connecting the upper rank unit and the USB device is provided from the input means.
3. A USB device using a USB interface, comprising: a USB connector for connecting a USB device to a USB or HUB in a host; a serial interface engine (SIE) serving as an interface interconnected by signal lines including a data line and a power supply line; and a switch for setting on/off state; a delay circuit provided between the USB connector and the serial interface engine for time-sequentially on-off switching the power supply line and the data line in accordance with the on/off state of the switch.
4. The USB device according to claim 3 , wherein the delay circuit interconnects the USB connector and the serial interface engine in the order of the power supply line and the data line when the switch sets on state and disconnects the USB connector and the serial interface engine in the order of the data line and the power supply line when the switch sets off state.
5. The USB device according to claim 3 , wherein the delay circuit interconnects the USB connector and the serial interface engine in the order of the power supply line and the data line after the lapse of a predetermined time since the power supply line connection when the switch sets the on state and disconnects the USB connector and the serial interface engine in the order of the data line and the power supply line after the lapse of a predetermined time since the power supply line disconnection when the switch sets the off state.
6. A USB device using a USB interface, comprising: a USB connector for connecting a USB device to a USB or HUB in a host; a serial interface engine serving as an interface interconnected by signal lines including a data line and a power supply line; and a switch for setting on/off state; a USB control unit for recognizing a signal indicative of power off transmitted from the host side through control transfer and transmitting a power off setting signal; a power supply control unit provided between the USB connector and the serial interface engine for time-sequentially on-off switching the power supply line and the data line in accordance with the on/off state of the switch and the power off setting signal from the USB control unit.
7. The USB device according to claim 6 , wherein the power supply control unit interconnects the USB connector and the serial interface engine in the order of the power supply line and the data line after the lapse of a predetermined time since the power supply line connection when the switch sets the on state and disconnects the USB connector and the serial interface engine in the order of the data line and the power supply line after the lapse of a predetermined time since the power supply line disconnection when the switch sets the off state or the power off setting signal from the USB control unit.
8. The USB device according to claims 3 or 6 , wherein the power supply line is provided with 5-V.
9. A power supply control method of a USB device using a USB interface having signal lines including a data line and a power supply line, wherein the power supply line and the data line are time-sequentially on-off switched in accordance with an on/off instruction.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
September 29, 1999
December 30, 2003
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